Facebook Says It Was Hacked, but No User Data Compromised

No user data was compromised as a result of hacking, reports CNBC's Julia Boorstin.

Facebook said on Friday it was the target of a series of attacks from an unidentified hacker group, but no user data were compromised.

"Last month, Facebook security discovered that our systems had been targeted in a sophisticated attack," the company said in a blog post. "The attack occurred when a handful of employees visited a mobile developer website that was compromised."